Determining Optimal Update Period for Minimizing Inconsistency in Multi-server Distributed Virtual Environments

Abstract

The primary task of distributed virtual environments (DVEs) is to maintain a consistent view of the virtual world among all users. Multi-server architecture has been shown to have good scalability to support a large population of users in DVEs. However, some of the servers' resources like CPU, memory and network bandwidth can still get saturated as the scale of DVE increases. In this case, state updates cannot be disseminated timely and the consistency of the virtual world cannot be guaranteed. In this paper, we investigate how to efficiently use the limited resources for state update to minimize inconsistency in multi-server DVEs. Using time-space inconsistency metric, we firstly prove that periodic state update will result in minimal inconsistency for each replica. Then, in order to determine the optimal update periods for replicas to minimize the total time-space inconsistency of the DVE, we formulate the problem as a convex optimization problem with inequality constraints. Finally, an interior point method is adopted to solve the problem and the performance is evaluated using simulation results.